1. Field of Invention
This invention relates to wireless communication and more particularly to a method and system for controlling when a radio link layer connection to a wireless terminal is released.
2. Description of Related Art
A wireless terminal is a form of telecommunication technology that enables people to communicate with others. The wireless terminal can take a variety of forms. The wireless terminal may be, for example, a cellular phone, a pager, a personal digital assistant (PDA), a portable computer with wireless modem, or a fixed wireless device.
The wireless terminal exchanges signals with a radio access network. The radio access network communicatively couples the wireless terminal to a remote terminal. The remote terminal may be, for example, another cellular telephone, a pager, a PDA, a portable computer with wireless modem, or a fixed wireless device.
The radio access network typically has a base transceiver station (BTS) and a base station controller (BSC) (collectively referred to as a “base station”). The wireless terminal exchanges signals with the BTS. In turn, the BTS exchanges the signals with the BSC. The BSC may be coupled to a mobile switching center (MSC) and a packet data serving node (PDSN). The MSC may facilitate communication with a public switched telephone network (PSTN) and the PDSN may facilitate communication with an IP network.
A properly equipped wireless terminal can initiate packet-data communications by sending an initiation request message to the MSC, via the BTS and the BSC. Applying industry standards, the initiation request message may include a “packet data” service option code that characterizes requested communication as packet-data communication, as compared to voice communication. The MSC may detect the packet data service option code when the MSC receives the initiation request and responsively send the message back to the BSC for handling.
In turn, when the BSC receives the initiation request from the MSC, the BSC may establish a radio link layer connection to the wireless terminal. In addition, the BSC may pass the initiation request to the PSDN. The PDSN and the wireless terminal may then negotiate with each other to establish a data link layer connection, typically a point-to-point protocol (PPP) session, to exchange packet data.
In most wireless communication systems, the radio access network may have an active-to-dormant timer. The active-to-dormant timer is set with a period of time indicative of when a radio link layer connection to the wireless terminal is released. The active-to-dormant timer starts when there is there is no activity over the radio link layer connection and stops when there is activity over the radio link layer connection. If the active-to-dormant timer expires, i.e., runs continuously for the period of time, then there is no activity over the radio link layer connection for the period of time. Responsively, the BSC may release the radio link layer connection to the wireless terminal.
The data-link layer (e.g., PPP) connection with the wireless terminal might remain, even though the radio link layer connection to the wireless terminal is released. Thus, the wireless terminal may still seek to send packet data to other entities, and other entities may still seek to send packet data to the wireless terminal. The BSC will page the wireless terminal over an air interface paging channel when another entity seeks to send packet data to the wireless terminal. When the wireless terminal receives a page indicative of an incoming data communication, or if the wireless terminal seeks to send data, the radio link layer connection with the wireless terminal will need to be re-established. To do so, the wireless terminal may send a message to the BSC to request radio link layer resources and the BSC may then establish a radio link layer connection to the wireless terminal. The wireless terminal may then send or receive packet data over the radio link layer connection.